A fellow Australian I follow on Twitter just said (September 1st there) it was the first day of spring. Growing up, the start of December, March, June and September were the start of summer, autumn, winter and spring respectively (or winter, spring, summer and autumn/fall for those of you in the northern hemisphere).
When I moved to the US, I noticed a lot of people talk as if the solstices and equinoxes were the seasonal boundaries.
This confused me because the solstices and equinoxes are technically the middle of the seasons, at least astronomically.
But thinking about that more, doesn't that mean that spring in the southern hemisphere (or fall in the northern hemisphere) really starts around August 8th? Not September 1st, not US Labor Day and not the equinox around September 22nd?